Abstract: The yield and the growth index of the underground part of cultivated Nardostachys chinensis Batal.were calculated and compared.The content of essential oil were determined by steam distillation,and the content of nardosinone were determined by HPLC,and then to analyze the change rule of product and effective constituents (essential oil and nardosinone).The results showed that the length,fresh weight and dry weight increased from May to September.Fresh weight and dry weight of three years growth were higher than that of two years growth,but the length was just the opposite.The content of essential oil was highest in July and there was litter difference between two years growth and three years growth.The content of nardosinone was highest in September,and the content of three years growth was higher than that of two years growth.The fastigiums of product,essential oil content and nardosinone content are different,so the optimal harvest time is September,three years growth according to the absolute content of effective constituents and the product of underground part.

Key words: Nardostachys chinensis Batal., harvest time, product, essential oil, nardosinone